Not too long ago I was teaching a class on how to write a romance story. Although my books are not strictly considered romance stories, they have elements of romance in them. For those interested in writing, I want you to consider this since none of the people I was teaching had considered this before. Read books on relationships written by therapists who specialize in relationships. This seems like a very simple thing to do, but not many people think about it. When you want to know about something, it is always best to hear from an expert.
When you have some understanding of what creates a positive relationship, and then look at some of the more popular romance stories, especially geared towards younger people, you will notice that they are actually extremely unhealthy relationships. Some common things you will notice within these teen romances would be controlling behavior, manipulation, and selfish actions that can cause some form of harm to their significant other. It is clear that these romantic relationships would not last or would become more destructive later on.
This is an incredibly dangerous thing to do, to write this for children, since it teaches them that this is normal, that these are positive relationships. In my works, I try to show the characters having positive relationships (unless it is necessary for the plot). To do that is actually incredibly simple. Each of the romantic, or hopeful romantic, characters display several characteristics necessary to have a positive relationship; a desire to support the other person, recognizing the positive and negative traits in the other person yet still accepting them for who they are, and wanting the other person to be happy. If you have those traits in a romantic character, and a good story to go along with it, then there is no reason for your romance story to not be good.